1. Field of the Invention
The present invention relates to a system and methods for notifying passengers of an approaching vehicle. Utilizing this invention, passengers can remain in a safe, controlled environment, avoiding harsh environmental conditions and excessive waiting times, instead arriving at their pick-up point just prior to a vehicle""s arrival. More specifically, the present invention relates to a bus notification system that will provide a passenger with adequate warning of an approaching bus well in advance of its arrival at the bus stop.
2. Background Art
In many cities and towns, school systems are required to provide transportation to and from school for children living more than a specified distance from school. Generally this transportation is in the form of busing whereby school buses pick up school children at several bus stops along several bus routes and then deliver the children to their school. The arrival time of a school bus at a given bus stop can vary significantly from day to day for any of a number of reasons. As a result, children typically arrive at the bus stop well before the bus is expected to arrive to avoid missing the bus. These children frequently lack parental supervision. Furthermore, on inclement weather days, children waiting for their bus are exposed to harsh weather conditions including rain, snow, or extreme cold. To avoid this situation, concerned parents frequently wait with their children at the bus stop in a car, causing unnecessary pollution.
Buses can be delayed for numerous reasons including inclement weather, such as fog, snow, ice or extreme cold, which reduces the speed of the bus and thus impedes the arrival of the bus at the planned time. Similarly, bus mechanical problems, heavy traffic or substitute bus drivers can generate lengthy delays in bus arrival time. In addition, many school buses will make several sequential runs to pickup children for different schools such as the high, middle and grade schools for a town. A delay in picking up children in the first run can result in similar or longer delays for subsequent runs. Correspondingly, it is possible, when there is good weather and light traffic conditions, for the bus to arrive at the bus stop earlier than the planned time.
In areas where bus routes cover many miles there frequently is a large variance in arrival time of a bus at the bus stops along the route and in many instances the bus stop will not be visible from the home. Similarly in areas where children live closer together, frequently there are communal bus stops for several children such that the bus stop is not visible from the home of each child. Advance notification of bus arrival also allows time to prepare the children for school without rushing to catch the bus.
There are many other situations where passengers and their families might find advance bus notification information useful. Children with special needs will especially benefit from such information, as they will have adequate warning time by which to prepare for boarding of the bus. Additionally, all passengers will be relieved of the shock factor of a bus pulling up unannounced.
There is disclosed in U.S. Pat. No. 4,325,057 a bus notification system wherein each bus transmitter emits a signal at a unique radio frequency to identify a specific bus. Each receiver is then tuned to the frequency corresponding to said bus transmitter and the length of time between notification and bus arrival is determined by adjusting the receiver""s sensitivity control. When the receiver acquires the bus transmission above the predetermined sensitivity threshold the notification system is activated.
Similarly, there is disclosed in U.S. Pat. No. 5,144,301 an alert system using different radio frequencies to identify particular buses and receivers that are tuned to the appropriate radio frequency wherein the time to bus arrival is approximated by comparing the received signal strength to an adjustable threshold setting. When the received signal strength exceeds the threshold, the receiver sequentially activates visual and audio warning signals.
In U.S. Pat. No. 5,021,780, there is disclosed an arrival notification where each bus emits an encoded signal uniquely identifying the bus and receivers in homes along the route are adjusted prior to distribution to receive only the encoded signal transmitted by the bus. The alerting mechanism in the receiver is activated upon detection of the encoded bus transmission using signal strength to estimate arrival time. However, the receiver does not incorporate a method for adjusting the alerting mechanism sensitivity. As a result, there is no available means to control the delay time between notification and bus arrival. Additionally, since the receivers in homes are adjusted prior to distribution, any bus changes or household moves to new buses introduces additional logistics problems.
In these disclosures, the time to bus arrival is approximated by the strength of the bus transmission signal received at the household. Signal strength, however, may not be an accurate measure of distance in every case because obstructions in the wireless radio frequency path can further reduce the signal strength thereby tricking the distance calculation by the receiver. The reduced signal strength can significantly reduce the time period between notification of bus arrival and the actual arrival of said bus. In addition, if the bus route includes several streets that are in close proximity requiring the bus to double back to cover said streets; the possibility for premature notification arises. Further, if two adjacent school districts use the same radio frequency, false alarms and premature notifications can result from two buses in neighboring districts broadcasting the same radio frequency.
A complex advance notification system for alerting passengers when a vehicle is ahead of or behind schedule is disclosed in U.S. Pat. No. 5,400,020. In this system, a vehicle control unit compares the actual time at which the vehicle reaches a predetermined location along the vehicle route against the scheduled arrival time, where the vehicle location is determined by global positioning system (GPS) technology. If there is a discrepancy between the actual and scheduled time values, the vehicle control unit relays the time discrepancy to a base station control unit by wireless communication. The base station control unit notifies each passenger of the change in arrival time by telephone. Thus, arrival time notification only occurs if the vehicle is off schedule. Further, the notification system requires that the telephone line be open and a person present to receive the telephone call. If the passenger is unable to hear the telephone ring such as when the phone is already in use or when the passenger is outside awaiting the arrival of the vehicle, the notification system will fail.
Another complex system for notifying passengers waiting for public transit vehicles of the status of transit vehicles, including expected arrival times of vehicles at transit stops and arrival of connecting transit vehicles is disclosed in U.S. Pat. No. 6,006,159. The disclosed system determines the location of transit vehicles by using a GPS device. The vehicle location is transmitted to a central facility wherein the central processor generates a master transit table for all vehicles calculating scheduled stops, connections to other transit vehicles and arrival times at each scheduled stop. The master transit table is subsequently broadcast to display devices located throughout the geographic area of the transit system including display devices in vehicles and transit stops. The display device stores the transit table or a subset thereof and displays selected information. In addition, the transit table or a subset thereof can be received by portable display means such as pagers, computers or telephones.
This transit notification system is appropriate for city or regional public transportation systems where the system involves a large number of passengers who are traveling between any two transit stops within the transit system and a large number of transit vehicles which are traveling on numerous transit routes within a large geographic area. The central facility must have sufficient resources to process a continuous data feed from each vehicle in the system to form updated transit tables and broadcast the transit table over the entire geographic area of the transit system. This system of notification requires a significant investment of resources in infrastructure development including installation of the central processing center, smart display devices throughout the transit system and vehicle information units in the transit vehicles.
Many passengers predominantly use a transit system to travel between two points such as a commute between home and work. The portable display devices disclosed in this patent are capable of displaying arrival information for a vehicle at a selected vehicle stop, but they can not alert a passenger that a vehicle will arrive at said vehicle stop within a predetermined period of time. Frequently, an automated notification process is desirable to alert the passenger that it is time to start the commute. A device capable of alerting such a commuter of the exact time by which to leave for their commute prior to leaving their controlled environment would be ideal.
In U.S. Pat. No. 5,680,119, there is described a vehicle identification system wherein types of vehicles such as emergency, school bus or other public transportation, delivery or service vehicles with emitters transmit an identifiable signal corresponding to the vehicle type. This patent does not describe a method for identifying a unique vehicle of a particular class, but rather only a method for determining the type of vehicle. Thus, the system merely differentiates between a school bus and an ambulance.
A receiving unit acquiring a RF signal broadcast from a nearby vehicle containing the correct information that is not actually picking up passengers can incorrectly notify passengers of a vehicle arrival at a specified point along the vehicle route. For example, one common passenger pickup technique is to drive all the way to the end of a vehicle route and then commence picking up passengers from the end of the route. This pickup technique poses problems for passengers near the beginning of the route, who are passed by the vehicle traveling in the wrong direction a considerable time before their vehicle actually stops to pick them up. In another example, public transportation vehicles frequently stop at each station in both directions along the vehicle route. Incorporation of a direction of travel parameter into the information transmitted from a vehicle would be especially valuable, allowing a receiving unit to only activate an alert mechanism when receiving a transmission from the correct vehicle traveling in a specified direction.
It thus would be desirable to provide a notification system that can more accurately predict a precise time of vehicle arrival such that a passenger""s waiting time for the vehicle is minimized. Such a notification system also should be less complex, less costly and not require extensive infrastructure as compared to prior art systems. Additionally, such systems and particularly the receivers therefor should be inexpensive and not require highly trained individuals to operate the equipment.
The present invention features a vehicle arrival notification system that will enable passengers to know the precise location and arrival time of the transporting vehicle several minutes before its arrival. The notification system comprises a transmission apparatus on a vehicle and receiving units at various locations along the vehicle route such as businesses, households, schools and the like. The transmission apparatus includes subsystems for determining the exact location of the bus and transmitting a signal including information identifying the vehicle route and the current vehicle location. The receiving unit compares the current vehicle location and direction of travel with information stored in its vehicle arrival log, thereby determining the time until the arrival of the vehicle at the specified location along the vehicle route. The alert function, either audio or visual, is activated when the receiving unit determined vehicle arrival time is less than an adjustable time threshold set by the passenger. The alarm function can also work off of a distance threshold, wherein the passenger sets an adjustable distance trigger to activate the alarm, the receiving unit determines the distance between the vehicle and the receiving unit with a simple distance calculation and the alarm is triggered when the calculated distance is less than the threshold.
In a preferred application of such a notification system, children and their parents are alerted to the approach of a school bus to pick up the children at a school bus stop. The accurate notification of an approaching school bus can minimize if not significantly eliminate the children""s wait at the bus stop and consequently their exposure to inclement weather. Children can spend a few extra minutes inside their home with their parents instead of enduring lengthy waits at the bus stop in potentially adverse conditions. In addition to notifying households of an approaching bus picking children up to go to school, the receiver will also alert parents of an approaching school bus dropping children off at the end of the school day.
The system includes the means to accurately determine the location of the vehicle and the location of any specified vehicle stop so that the distance between the vehicle and the vehicle stop and the corresponding time can be accurately measured. Global positioning satellite (GPS) technology generates extremely accurate location coordinates by analysis of signals from a plurality of global positioning satellites. Receiving units within the range of the transmission apparatus"" RF signal receive the GPS determined location of the vehicle regardless of the strength of the RF signal and calculate the distance between the vehicle and the vehicle stop using GPS determined locations for both the vehicle and the vehicle stop. Unlike systems relying on signal strength to determine the distance that are subject to inaccuracies resulting from obstructions in the wireless radio frequency path, the vehicle location as determined by GPS is independent of signal strength. As a result, a receiving unit can accurately calculate an associated arrival time and the distance between receiving unit and vehicle, thereby providing accurate arrival information.
In specific embodiments, the system further includes the means to determine if an approaching vehicle is traveling in a specified direction so that passengers are only notified when a vehicle is approaching a vehicle stop from a specified direction. The transmission apparatus further includes the means to determine the direction of vehicle travel by GPS technology and transmit a signal further including information about the a direction of vehicle travel. Each receiving unit further compares the received direction of vehicle travel with a specified direction of vehicle travel such that an alarm function is activated when the vehicle is closer than a specified threshold location and traveling in the specified direction.
In preferred embodiments of the invention, the receiving unit further includes the means to acquire information about a vehicle by a simple information acquisition protocol herein referred to as the learn function. Activating the learn function when a vehicle approaches the vehicle stop causes the receiving unit to acquire the vehicle route number and direction of vehicle travel from the vehicle transmission unit signal. The receiving unit location coordinates are also acquired by the receiving unit from the bus transmission unit signal. After the learn function has been activated, the receiver listens for the transmission signal of greatest amplitude. When signal amplitude is maximized and distance between the transmitter and receiver is minimized, the bus stop location is stored into the receiver memory. Alternatively, the bus stop location can be simply stored into the receiver memory when the learn button is depressed.
Additional information is also transmitted from the transmitter to the receiver at this time. More specifically, a historical log file that includes vehicle location and direction of travel for at least one time entry is stored into the receiver""s memory so that this data can be later accessed to understand exactly how the bus approached the bus stop. Preferably, the historical log file includes at least five minutes of time entries wherein sequential time entries are separated by a small time increment such as 10-30 seconds. As a result, the vehicle information acquired by the receiving unit during the learn function is used by the notification system to determine when to alert passengers that their specific vehicle is approaching.
In another embodiment of the present invention, the transmission apparatus further includes the means to electronically store information about the vehicle during operation. A vehicle log file is generated including an entry for each transmitted RF signal such that each entry includes a time mark and the transmitted vehicle location coordinates. Each vehicle log file entry can further include additional information such as vehicle speed and/or direction of vehicle travel. Information stored in a vehicle log file can be downloaded to a PC for use in monitoring vehicle operation. The information contained in the vehicle log files can be used to monitor vehicle operator performance and to determine the validity of passenger complaints regarding vehicle operation.
In a preferred embodiment of the present invention, the system includes a transmission apparatus that can be programmed with new vehicle information and to download information stored in a vehicle log file. A transmitter pendant interfaces with a transmission apparatus such that the pendant can display current transmission apparatus information and introduce new information. The transmitter pendant can further include an apparatus to download information stored in the vehicle log file of the transmission apparatus and transfer this information to a PC.